[ddc] Fix missing super getter and setter helpers
[ddc] Fix missing super getter and setter helpers

Previously only a super helper would be created as needed when there was
a super getter or setter call a constructor. If both a get and set exist
only the first encountered would trigger a helper to be generated. The
second helper would be missing and the call to it would trigger an
exception.

Now the helpers are tracked with unique names to avoid collisions.

Fixes: https://github.com/dart-lang/sdk/issues/47698
Change-Id: I561adc0ce8f97e81a9e12d749d4d80e1f5e73f38
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/221743
Commit-Queue: Nicholas Shahan <03847abd2d8aadfe859ecb98095a31f9f515dc47@google.com>
Reviewed-by: Mark Zhou <654f5fe0c4ca6c799b0e735dcf3fc1c389f35bf9@google.com>

dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk